Neil, pls tell why do you need the correlation matrix? if you are trying to simulate correlated variables then you can go around the cholesky by using svd. if you really need the correlation ( I think it is always possible to avoid it ) then Rmetrics have a function to turn your matrix into positive semi-definite. you can also consider a factor model which will reduce the dimensionality tremendously. Stephen C. Bond
On Apr 1, 2009, ngottl...@marinercapital.com wrote: Dear fellow R Users: I am doing a Cholesky decomposition on a correlation matrix and get error message the matrix is not semi-definite. Does anyone know: 1- a work around to this issue? 2- Is there any approach to try and figure out what vector might be co-linear with another in thr Matrix? 3- any way to perturb the data to work around this? Thanks for any suggestions. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.